The present invention relates generally to radiant energy transmission and more particularly to improved devices for the efficient transmission of energy emanating from a geometrically convex source to a geometrically convex receiver.
Applicant's publication appearing in Solar Energy Vol. 16, No. 2, pages 89-95 (1974), as well as his U.S. Pat. Nos. 3,957,031, 4,002,499, 4,114,592 and 4,130,107 describe techniques for generating the ideal reflective wall contour for certain energy transmission (i.e., collection and emission) devices. Applicant's U.S. Pat. No. 4,240,692, issued Dec. 23, 1980, is addressed to shaping of such ideally reflecting walls in a manner consistent with assuring total internal reflectivity for the devices. Such concentrator devices are generally characterized by a suitable reflective wall contour (parabolic, elliptical, etc.) permitting extreme incident rays from an energy source to be transformed, after at most one reflection, into the extreme rays incident on an energy absorbing body. In each case the reflective wall contour is shaped to assume the maximum possible slope consistent with reflecting the extreme rays onto the absorber, subject to accommodation for such subsidiary conditions as specification of a selected maximum angle of incidence along the absorber or a requirement that reflection along a portion of the wall be accomplished by total internal reflectivity. In all such cases, however, the extreme incidence rays treated were those emanating either from a "point" source located at infinity or a source which is flat and located at a finite distance from the concentrator.
There exists a long standing need in the art of energy transmission for devices capable of high efficiency in transmitting radiant energy from a convex source to a convex receiver located at a finite distance from the source. Examples of such devices include lamps intended to uniformly illuminate a convex surface with direct and reflected energy from, e.g., a fluorescent light tube. The need to assure efficient, uniform energy transmission is particularly acute in the design of cavity pump systems for the transformation of the power spectrum of a flash tube to that within the space occupied by a rod of lasing material. A wide variety of designs for mirror cavity systems have been proposed in the laser art (see, e.g., Mahlein, et al., Laser Devices and Techniques pp. 508-517 in "Laser Handbook", Vol 1., North Holland Publishing, Amsterdam, Holland (1972) but none have consistently achieved the desired optimal levels of energy transfer efficiency.